1. Field of the Invention
The present invention relates to controls for enhanced upshifting in an at least partially automated mechanical transmission system including an inertia brake. In particular, the control relates to inertia brake controls for an automated transmission system shifting without disengaging the master clutch. In such systems, in the absence of protective logic, the inertia brake might be subject to undue wear and/or damage.
2. Description of the Prior Art
Vehicular drivetrains including multiple-speed transmissions, usually compound transmissions, or simple transmissions coupled with multiple-speed axles, having 5, 6, 7, 9, 10, 13, 16, 18 or more forward speed ratios, are well known in the prior art, especially for heavy-duty vehicles, as may be seen by reference to U.S. Pat. Nos. 5,370,013; 5,527,237 and 4,754,665, the disclosures of which are incorporated herein by reference.
Fully and partially automated vehicular mechanical transmission systems are well known in the prior art, as may be seen by reference to U.S. Pat. Nos. 4,361,060; 4,595,986 and 4,648,290, the disclosures of which are incorporated herein by reference. U.S. Pat. No. 4,361,060 discloses logic for determining when an upshift or downshift is indicated.
Fully and partially automated mechanical transmission systems which are dynamically shifted while maintaining the master clutch engaged also are well known in the prior art, as may be seen by reference to U.S. Pat. Nos. 4,850,236; 5,435,212 and 5,735,771, the disclosures of which are incorporated herein by reference.
Vehicular inertia brakes, also called input shaft brakes and upshift brakes, also are well known in the prior art, as may be seen by reference to U.S. Pat. Nos. 5,528,950 and 5,713,445, the disclosures of which are incorporated herein by reference.
Automated transmission systems wherein input shaft and/or engine braking is utilized to complete and/or decrease the time required for upshifts are known in the prior art, as may be seen by reference to U.S. Pat. Nos. 5,425,689 and 5,655,407, the disclosures of which are incorporated herein by reference.
In a system allowing application of the inertia brake while the master clutch is engaged, an increased potential for excessive wear or damage to the inertia brake exists in the absence of protective logic for the inertia brake.